Type resolution for complex class hierarchy

[thedeadferryman]

Let's say we have class structure like this:

Classes in green are interfaces and there are corresponding type declarations in graphql schema. But the resolver returns instances of actual classes (highlighted in blue). When it comes to type resolution, DictionaryTypeResolver takes superclasses first, not interfaces, so the resolution sequence looks like this (for FolderImpl): FolderImpl -> FSNodeImpl -> FSNode -> gql interface FSNode. As a result, it fails with an error of FSNode being an interface, not an object type.
However, the resolution sequence I expected is FolderImpl -> Folder -> gql objtype Folder.
I understand that this may be expected behavior, but the question is: in what way can this be solved besides just removing FSNodeImpl from the class structure?